The importance of the ETRTO standard for bicycle tires.

Bicycles come in many different sizes. Accordingly, tubes and tires also have individual dimensions. In the following article, we explain how to determine the right size for your bike with ETRTO.

What does the ETRTO standard mean for bicycle tires?

The ETRTO standard (European Tyre and Rim Technical Organization) ensures that tires and rims are uniformly marked worldwide, putting an end to confusing inch and inch size specifications such as “28 inch” or “700C”, which can vary depending on the manufacturer.

Why is this important?

Thanks to the ETRTO standard you can be sure that the tire and rim fit together perfectly. This reduces the risk of fitting problems and increases safety when riding.

Advantages of the ETRTO standard.

  • Standardized size specifications worldwide
  • Simple tire change without guesswork
  • More security and compatibility

How do you read the ETRTO specification?

A typical example: 40-622

40 = Tire width in millimeters
622 = Inner diameter of the rim in millimeters

This means: This tire is 40 mm wide and fits on a rim with a diameter of 622 mm (corresponds to about 28 inches).

What tire sizes are available?

Tire size table Download

You should find almost every known size designation in this list. We have tried to include all size designations that are used in the market or were used in the past.

Why are inch markings on bicycle tires often confusing?

Tires with the designations 28 inch and 29 inch both have the same Rim inner diameter of 622mm. This means that they theoretically fit on the same rims.

28 inch is the classic size for touring bikes in Europe and is very widespread.

29 inch was later introduced in the USA for mountain bikes. The name comes from the fact that the tires are thicker there and the Outer diameter is approximately 29 inches.

Why is this information inaccurate?

The inch size does not refer to the rim diameter, but to the outer diameter of the complete wheel - and this depends on the tire width.

  • A narrow road bike tire (e.g. 23 mm) actually only has about 26 inch Outside diameter
  • With a width of approx. 40 mm you get approximately 28 inch
  • Very wide tires (60 mm or more) reach almost 30 inch

Conclusion:

Die Zollangabe ist nur ein grober Richtwert. Für eine exakte Passform ist die ETRTO-Angabe (z.B. 37-622) entscheidend, denn sie gibt den Felgendurchmesser und die Reifenbreite in Millimetern an.